Litoquímica, geocronologia U-Pb e Geologia isotópica (Sr-Nd-Pb) das rochas graníticas dos batólitos Cunhaporanga e Três Córregos na porção sul do Cinturão Ribeira, Estado do Paraná

Authors

  • Hélcio José dos Prazeres Filho Universidade de São Paulo; Instituto de Geociências; Programa de Pós-Graduação em Geoquímica e Geotectônica
  • Ossama Mohamed Harara Universidade de São Paulo; Instituto de Geociências; Programa de Pós-Graduação em Geoquímica e Geotectônica
  • Miguel Angelo Stipp Basei Universidade de São Paulo; Instituto de Geociências; Departamento de Mineralogia e Geotectônica
  • Cláudia Regina Passarelli Universidade de São Paulo; Instituto de Geociências; Centro de Pesquisas Geocronológicas
  • Oswaldo Siga Jr. Universidade de São Paulo; Instituto de Geociências; Departamento de Mineralogia e Geotectônica

DOI:

https://doi.org/10.5327/S1519-874X2003000100005

Keywords:

Ribeira belt, granitic batholiths, geochronology, isotopic geochemistry

Abstract

During evolution of the southern part of the Ribeira Belt in Paraná State, the Brasiliano-Pan-African Cycle was responsible for the generation of a large volume of granitic rocks among which the Cunhaporanga (BCP) and Três Córregos (BTC) batholiths stand out. Studies of rock chemistry and isotopic compositions show that differences exist both between and within the batholiths. The main difference between the batholiths is in the behaviour of the alkalies. The BCP is more potassic, while the BTC is more sodic. The isotopic data clearly show the participation of different lower crustal sources with long crustal residence times, given by the isotopic composition of Pb in K-feldspar, by the negative values of µNd (-11 to -13 for BCP and -17 to -19 for BTC), and by the model Nd T DM ages (1.8 - 2.0 Ga for BCP and 2.2 - 2.4 Ga for BTC). These sources are situated in Paleoproterozoic continental crust, and different proportions of mantle and crustal contributions are involved in the genesis of the BCP and BTC granites. The Ribeirão Butiá Unit of the BCP and the Arrieiros and Paina units of the BTC are mainly composed of monzogranite and granodiorite with rare tonalite, comprising metaluminous, medium- to high-K calc-alkaline rocks formed between 630 and 620 Ma at an active continental margin. The Piraí do Sul and Santa Rita units of the BCP are formed by slightly peraluminous, high-K monzogranite, while the São Sebastião and Conceição units of the BTC are composed of high-K, slightly metaluminous quartz monzonite and monzo- to syenogranite, respectively. These units were formed under a syn- to late-collisional regime between 620 and 590 Ma.

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Published

2003-08-01

Issue

Vol. 3 (2003)

Section

Articles

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How to Cite

Prazeres Filho, H. J. dos, Harara, O. M., Basei, M. A. S., Passarelli, C. R., & Siga Jr., O. (2003). Litoquímica, geocronologia U-Pb e Geologia isotópica (Sr-Nd-Pb) das rochas graníticas dos batólitos Cunhaporanga e Três Córregos na porção sul do Cinturão Ribeira, Estado do Paraná . Geologia USP. Série Científica, 3, 51-70. https://doi.org/10.5327/S1519-874X2003000100005